I need a WHERE statement where the date of the record is the previous day. I have the below code which will do this
WHERE DOC_DATE = dateadd(day,datediff(day,1,GETDATE()),0)
However I need this statement to get Friday's record when the current day is Monday. I have the below code but it will not work for me. No errors come back on SQL although no records results come back either. I have the below code for this
WHERE DOC_DATE = DATEADD(day, CASE WHEN datepart(dw,(GETDATE())) IN (2) then -3 ELSE -1 END ,0)
Important to add that this needs to be in a WHERE clause. This is for a Docuware administrative view I am creating. I have no control on how to write the SELECT statement, I only have access to edit the WHERE clause:
Here's a slightly "magical" way to compute the value that doesn't depend on any particular server settings such as datefirst. It's probably not immediately obvious how it works:
WHERE DOC_DATE = dateadd(day,datediff(day,'20150316',getdate()),
CASE WHEN DATEPART(weekday,getdate()) = DATEPART(weekday,'20150330')
THEN '20150313'
ELSE '20150315' END)
In the first line, we're computing the number of days which have elapsed since some arbitrary date. I picked a day in March 2015 to use as my base date.
The second line asks what today's day of the week is and if it's the same as some arbitrary "Known good" Monday. Just taking one value and comparing it to 2 depends on what your DATEFIRST setting is so I prefer not to write that.
In the third line, we decide what to do if it's a monday - I give a date that is 3 days before my arbitrary date above. If it wasn't a monday, we pick the day before.
Adding it all together, when we add the days difference from the arbitrary date back to one of these two dates from lines 3 and 4, it has the effect of shifting the date backwards 1 or 3 days.
It's can be an odd structure to see if you're not familiar with it - but combining dateadd/datediff and exploiting relationships between an arbitrary date and other dates computed from it can be useful for performing all kinds of calculations. A similar structure can be used for computing e.g. the last day of the month 15 months ago using just dateadd/datediff, an arbitrary date and another date with the right offset from the first:
SELECT DATEADD(month,DATEDIFF(month,'20010101',GETDATE()),'19991031')
As I said in a comment though, usually doing this sort of thing is only a short step away from needing to properly model your organisation's business days, at which point you'd typically want to introduce a calendar table. At one row per day, 20 years worth of pre-calculated calendar (adjusted as necessary as the business changes) is still less than 10000 rows.
You can try this.
WHERE DOC_DATE = DATEADD(DAY, CASE WHEN datepart(dw, GETDATE()) = 2 THEN -3 ELSE -1 END, CAST(GETDATE() AS DATE))
Related
I am not a SQL user, it happens that I need to know what this type of SQL code means, can you help me please translating it to me?
CASE
WHEN DATEDIFF(to_date(B.DT_CAREPACK_END),
LAST_DAY(date_sub(add_months(current_date, 3), 20))) > 0
CASE statements let you introduce some conditional logic.
A full CASE sttatement would have a syntax like:
CASE
WHEN some logic is true THEN x
WHEN some other logic is true THEN y
ELSE THEN z
END as column_title
In your example, it doesn't look like you've provided the full statement as their is no END keyword.
Basically, this logic is checking when the difference between two dates (date-x and date-y) is positive or not. DATE_DIFF looks at the different between a start date (date-x) and an end date (date-y).
If date-x, the start date, is before date-y, the end date, then the result is positive. If the start date is after the end date, then the result is negative.
date-x is a date representation of the column DT_CAREPACK_END
date-y is taking the current_date, adding on 3 months (e.g. 4th September becomes 4th December), is is then subtracting 20 units (presumably days) and then setting that date to the last date of that month.
So, imagine DT_CAREPACK_END (presumably a date when something ends) is in the future and is 2022-10-02.
The inner logic here will take the current date (2022-09-04) and add 3 months to that date, making it 2022-12-04. Then, we are subtracting 20 days which is 2022-11-14. Then, we find the last day in that month, which would be 2022-11-30.
Finally, we look at the difference between 2022-10-02 (start date) and 2022-11-30 (end date). If that is a positive number, then the logic is satisfied. In this case, 2nd October is before 30th November, resulting in a positive logic and therefore the case logic is satisfied.
If the DT_CAREPACK_END is before the current_date logic, then it would be negative.
*N.B. I thought that date_add, date_sub and date_diff functions needed an interval unit to be explicitly stated (e.g. INTERVAL 20 DAY). I'm guessing the default here is days but that's an assumption on my part. I'm working in good-faith that the code snip is syntatically correct. *
Resources:-
Add Months:
https://docs.oracle.com/cd/B19306_01/server.102/b14200/functions004.htm
Date Sub:
https://docs.oracle.com/cd/E17952_01/mysql-5.7-en/date-and-time-functions.html#function_date-add
Last Day:
https://docs.oracle.com/cd/E17952_01/mysql-5.7-en/date-and-time-functions.html#function_last-day
I need to add the week day from previous year on the 3rd column.
Form example 06/02/2021 was on a Wednesday. I need the week day of 06/02/2021.
Thanks
try this:
SELECT DATENAME(weekday,DATEADD(YEAR, -1, '06-02-2021'))
Tableau is notoriously difficult to figure out work days. As some have suggested, it may be easier to use the underlying database to calculate this. However, if you need to do this in Tableau it can be accomplished like this:
DATEADD(
"day"
,CASE LEFT(LOWER(DATENAME("weekday",[DateFieldUsed])), 3)
WHEN 'fri' THEN 3
WHEN 'sat' THEN 2
ELSE 1
END
,[DateFieldUsed]
)
Basically, if it is Friday you need to add 3 days to the date, Saturday you need to add, and in any other situations just add 1 date. (please test, not doing this in Tableau so the numbers may be off).
I may have misunderstood the question, the example isn't exactly what you're asking. If your current value is 6/2/2021, and you are trying to find the week day of 6/2/2020, I would do this:
DATENAME("weekday", DATEADD(year, -1, [DateFieldUsed])
I work for a company where everyday I modify a query by changing the date of the day before, because the report is always from the previous day.
I want to automate the date change. I have made a table with two columns, one with all dates from this year and another with bits where if 0 is a working day and 1 if is a holiday.
I have successfully automated a little bit by telling if the day before is a working day then subtract 1 from the date (This is what happens everyday). But the problem is, that if is Monday appears as Friday, because Saturday and Sunday are not billable. And let's also say, that if today is Thursday and Wednesday and Tuesday we're holidays, then the report will run on Monday. I will leave you a picture, that shows how the table is made with dates.
Remembering, that if there is no holidays in the middle of the week, always will be subtract one.
The way to do this sort of thing is close to what you have done, but just extend it further. Create a BusinessDate table that has every date, and then every rule you have implemented inside it. You can go so far as to include a column such as ReportDate which will return,for every date, what date the report should be run for.
Do this once, and it will work forever more. You may have to update for future holidays once a year, but better than once a day!
It will also allow you to update things specific for your business, like quarter dates, company holidays, etc.
If you want to know more on the subject, look up topics around creating a date dimension in a data warehouse. Its the same general issue you are facing.
Too complicated for a comment and it involves a lot of guessing.
So everyday, your process starts by first determining if "today" is a work day. So you would do something like:
if exists (select * from <calendar> where date = cast (getdate() as date) and IsWorkday = 1")
begin
<do stuff>
end;
The "do stuff" section would then run a report or your query (or something that isn't very clear) using the most recent work day prior to the current date. You find that date using something like:
declare #targetdate date;
set #targetdate = (select max(date) from <calendar>
where date < cast (getdate() as date)
and IsWorkday = 1);
if #targetdate is not null
<run your query using #targetdate>
That can be condensed into less code but it is easier to understand when the logic is written step-by-step.
I know this one is pretty easy but I've always had a nightmare when it comes to comparing dates in SQL please can someone help me out with this, thanks.
I need to get the month and year of now then compare it to a date stored in a DB.
Time Format in the DB:
2015-08-17 11:10:14.000
I need to compare the month and year with now and if its > 12 months old I will increment a count. I just need the number of rows where this argument is true.
I assume you have a datetime field.
You can use the DATEDIFF function, which takes the kind of "crossed boundaries", the start date and the end date.
Your boundary is the month because you are only interested in year and month, not days, so you can use the month macro.
Your start time is the value stored in the table's row.
Your end time is now. You can get system time selecting SYSDATETIME function.
So, assuming your table is called mtable and the datetime object is stored in its date field, you simply have to query:
SELECT COUNT(*) FROM mtable where DATEDIFF(month, mtable.date, (SELECT SYSDATETIME())) > 12
I have a table in a database with one column containing dates and another one containing scores. Basically, what I want to do is grab the best score in a given week.
Weeks can start on any given day (From Friday to Thursday, for instance), and that is defined by the user.
Here is what I have so far:
SELECT MAX(Series), DATE(DATE(Date, 'weekday 0'), '-7 days') dateStartOfWeek FROM SeriesScores
WHERE Season = '2010-2011'
AND dateStartOfWeek = '2010-08-29'
GROUP BY DateStartOfWeek
Where Series is the column containing the scores and Date is the (badly) named actual date.
The problem with this query is that it works for every day except for the day the week is supposed to be starting on.
For example: 2010-08-29 is a Sunday and in this example, I'm trying to find on which date the Sunday of the given week is. My function works for every day of that week except for 2010-08-29 (Sunday) since it tries to find the next day that is a Sunday (itself in this case). To compensate for that, I go back 7 days to get the correct Sunday, which creates the error for the already correct Sunday since this one doesn't need to go back 7 days or else it is one week off.
I figured I could solve this problem easily using Java, but I want to see how it should be done using SQL instead.
My solution (I don't even know if it can be done), would be to check if date and dateStartOfWeek are the same. If they are, don't substract 7 days from the date. If they're not, do as I did in my example. I don't know how to use conditions such as this one in SQL, though, and this is where I need help.
Thanks a lot in advance!
I think you need to use CASE operator - see http://sqlite.awardspace.info/syntax/sqlitepg09.htm
EDIT - try:
SELECT MAX(Series), CASE WHEN STRFTIME ( '%w', Date ) = 0 THEN DATE(Date, 'weekday 0') ELSE DATE(DATE(Date, 'weekday 0'), '-7 days') END AS dateStartOfWeek FROM SeriesScores
WHERE Season = '2010-2011'
AND dateStartOfWeek = '2010-08-29'
GROUP BY DateStartOfWeek
see http://www.sqlite.org/lang_datefunc.html